1. Field of the Invention
This invention relates to an operating device for a transmission.
2. Description of the Prior Art
Recent types of manual transmission for a large-sized vehicle such as a bus or truck have been provided with an operating device in which a manual speed-change operation of the transmission is boosted by electric energy or hydraulic pressure etc. and transmitted to the transmission so as to facilitate the speed-change operation of the transmission.
One example of these prior art devices will be described with reference to FIGS. 1 to 3.
The device shown in FIG. 1 is for a bus, wherein it is composed of an instruction unit A located at the driver's seat, a signal processing unit B having relay circuits or the like and a gear-shift unit D arranged at the transmission C.
In the instruction unit A, the switches S.sub.1 and S.sub.2 acting as a signal generating means shown in FIG. 3 are operated by operating the manual operating member to a speed-change position corresponding to the shift pattern shown in FIG. 2. In this case, the switch S.sub.1 indicates a shift direction Q.sub.1, Q.sub.2 and Q.sub.3 of said shift pattern and the switch S.sub.2 indicates the positions of selecting direction P.sub.1, P.sub.2 and P.sub.3 in the pattern and their signals are fed to the gear-shift unit D constituting a booster device after they are processed in the signal processing unit B.
The gear-shift unit D has a solenoid valve which is operated by the signals and a power cylinder supplied with air under pressure from an air tank through the solenoid valve so as to operate a selection fork or a shift fork of the transmission and varies the engagement condition of the transmission C in an order of the selecting direction and then a shift direction in reference to an output signal from said signal processing unit B which is fed to solenoid valve. The gear-shift unit D is provided with switches for detecting the engaged position of the gears and the signals P.sub.1 ', P.sub.2 ' and P.sub.3 ', and Q.sub.1 ', Q.sub.2 ' and Q.sub.3 ' shown in FIG. 3 from the switches serve as shift completed signals and then selecting completed signals to the signal processing unit B so as to cut off the output signals P.sub.1, P.sub.2 and P.sub.3, and Q.sub.1, Q.sub.2 and Q.sub.3 from the signal processing unit B. When the transmission is performed for its speed-change operation through booster means such as a gear-shift unit operated under the energy of air pressure or the like, the operator does not operate the transmission directly and the force required for operating the speed-change operation is quite low, so that the operator may not sense completion of the speed-change operation of the transmission and sometimes may feel a sense of uneasiness, resulting in affecting an operator's concentration on the driving operations other than the speed-change operation.